I am searching someone who knows structures of x files and is familiar with skinned animations in directx. I am familiar too quite well (I even wrote directx exporter to x file for blender), however I have the problem which I completely don't understand. I have mesh and move only one bone. And in blender everything is OK. After export to .X file in directX viewer I see that vertices which doesn't belong to the bone are moved too and part of bone vertices are not moving. The animated bone is the last in hierarchy and moreover after x file inspection I don't see any issue.

If someone might do the inspection of this file as well I would be grateful. Mesh has only 51 vertices (originally I have problem with Human mesh which has 10,000 vertices, however I managed to reduce the mesh for which the problem is reproducible to 51 vertices). I am really desperated because I dedicated about 30 hours in the last two days to solve the issue and I am completely lack of idea.